Currently, passengers in aircraft need to deactivate their mobile RF communication devices at least during take-off and landing. Mobile RF devices try to maintain connectivity to terrestrial cellular networks on the ground. Due to the high speed of the aircraft and the increasing altitude, large path losses, high fading and delay interference may occur forcing the internal transceivers in the mobile devices to operate at full power. Apart from RF interference issues with electronic equipment on board of the aircraft, frequent base station handovers and cell roaming would cause terrestrial network disturbances.
Usually, on-board ground network suppressors (OBCEs) are employed in aircraft to jam or block all mobile RF communication signals from terrestrial network stations above a flight height of 3 kilometers.
Document US 2011/0211489 discloses a communication method in an LTE multi-carrier system, in which radio resources for transmitting signals to a middle guard band are allocated and transmitted through the radio resources. The middle guard band is a frequency band positioned between used bands of a plurality of carriers of an aggregated carrier. This middle guard band between the carriers is used to improve channel estimation performance or to increase efficiency of radio resources.
Document DE 10 2011 119 892 A1 discloses a method of controlling a mobile communication network on board of an aircraft including combining an LTE service signal in a first frequency band with a masking signal in a second frequency band to suppress reception of terrestrial mobile communication signals in both frequency bands.
Document DE 10 2011 079 972 A1 discloses a communication method on board of aircraft which uses a masking signal to both disrupt mobile communication with terrestrial communication base stations as well as convey information items to onboard media equipment within the masking signal.